Porcine Rotaviruses
LEVELS: Rarely occurs; No human illness; Already in the herd; Laboratory-dependent; Minor; Negligible; Little; Available but inconsistent
| Register id | porcine_rotaviruses |
| Type | virus |
| Scientific name | Porcine rotavirus |
| NCBI taxid | 10913 |
| Evidence | 2 document(s) |
| Assigned | 2026-09-04, against criteria version 093366e352a2 |
Overview
This entry covers the four rotavirus species commonly found in pigs — A, B, C and H — as one unit. Rotaviruses are a leading cause of diarrhoea in young pigs and are entirely unavoidable: they are ubiquitous, every pig will be infected at least once in its life, sows shed virus at farrowing, and the particles are highly resistant in the environment. Rotavirus A was long considered the most important, but rotavirus C is now recognised as a significant cause of enteritis in newborn piglets, while B and H affect younger and older pigs respectively. Diarrhoea in pigs infected under a week old lasts one to ten days and most recover; mortality in conventionally reared piglets is usually below 20%, though it is far higher in diagnostic cases and in germ-free experimental pigs. Infection can also be entirely silent, which matters diagnostically, because the clinical signs are indistinguishable from those of other enteric agents and finding the virus does not by itself explain a case — RT-PCR plus the clinical picture is what makes a diagnosis. Treatment is supportive: warmth, fluids, electrolytes, and antibiotics for the bacterial infections that follow. Commercial vaccines exist for rotavirus A but not for B or C, there is no cross-protection between groups, and maternal antibody can interfere with live vaccines. Direct animal-to-human transmission has not been shown to occur naturally, though it is possible experimentally.
C1 Zoonotic potential
Likelihood of transmission from pigs to humans
Rarely occurs: Human infection from pigs is plausible but has only rarely been reported, and specific control points are not commonly implemented to prevent transmission to humans
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c1l2, i think has to be l2 because is plausible"
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.3, a Public Health section that answers the criterion from both directions: "ALTHOUGH DIRECT TRANSMISSION OF RVs FROM ANIMALS TO HUMANS HAS NOT BEEN FOUND TO OCCUR UNDER NATURAL CONDITIONS, it has been demonstrated EXPERIMENTALLY that RVs isolated from one animal species, or humans, can infect another animal species. Additionally, THE DETECTION OF ANIMAL-HUMAN REASSORTANT RVA STRAINS IN HUMAN PATIENTS HAS SUGGESTED A ZOONOTIC POTENTIAL FOR RVA... PORCINE-LIKE RVC WAS DETECTED IN CHILDREN IN BRAZIL and human-like RVCs were found in pigs, PROVIDING EVIDENCE OF THE ZOONOTIC POTENTIAL OF RVCs. Sequence analysis of RVC strains circulating in Japan, India, the United States, Mexico, and Europe also REVEALED INTERSPECIES TRANSMISSION OF RVC. However, HOST-SPECIFIC GENOTYPES FOR RVB AND RVH SUGGEST THE ABSENCE OF TRANSMISSION between swine and humans for these RV species."
How this level was decided
RE-READ AND HELD AT L2 2026-09-04 AGAINST THE REWORDED LABELS. FLAG. ch38 38.2.3: "PORCINE-LIKE RVC WAS DETECTED IN CHILDREN IN BRAZIL" and animal-human reassortant RVA strains have been found in patients -- porcine-like virus in a child is close to attribution. Against it, the same section opens "DIRECT TRANSMISSION OF RVs FROM ANIMALS TO HUMANS HAS NOT BEEN FOUND TO OCCUR UNDER NATURAL CONDITIONS".
PREVIOUS ANSWER, kept because the evidence behind it has not changed, only the level boundary: Level 2, FLAGGED, and this is the cell in the batch most likely to move, so both readings are set out. LEVEL 2 IS SCORED: human infection from pigs is plausible and has rarely been reported, and no control point is implemented against it -- which is the label. The evidence for "rarely reported" is genetic rather than epidemiological: porcine-like RVC in Brazilian children, animal-human reassortant RVA strains in patients, and sequence analysis across five regions showing interspecies transmission of RVC. THE ARGUMENT FOR LEVEL 1 IS THE CHAPTER'S OWN FIRST CLAUSE -- direct transmission from animals to humans HAS NOT BEEN FOUND TO OCCUR UNDER NATURAL CONDITIONS -- and it fits the pattern you have now ruled on five times, most recently on Sarcoptes: "the literature overrates the potential... human infection is plausible and described, just very infrequent", and on Staphylococcus hyicus, "though isolated from humans rarely it is MISLEADING TO CONSIDER IT A CONSEQUENTIAL ZOONOSIS." WHAT MAKES THIS ONE ARGUABLY DIFFERENT: the pig-attribution link is stronger than in those cases, because a PORCINE-LIKE virus was found in a child rather than a human infection being found and a pig source assumed. Two of the four member species are host-specific and transmit neither way.
C2 Zoonotic impact
Severity of human illness caused by the agent
No human illness: Agent does not cause illness in people
Corrected by Eric from L2 Mild. Reason: HELD AT LEVEL 1 AGAINST THE RE-SCORED PASS, 2026-09-04. His markup: "rota c2l1". The pass had moved this cell to level 2 on the reworded C2, reasoning that human rotavirus gastroenteritis is a real illness and that C2 now grades the agent rather than the pig-attributable route. HE OVERRULES THAT, and the ruling is consistent with his 2026-09-03 reasoning on the same entry -- "even though it is a plausible zoonosis, rotaviruses are VERY SPECIES SPECIFIC so until some evidence comes to light, I ASSUME THEY ARE MORE LIKELY TO BE INCIDENTAL INFECTIONS". READ AS A C2 STATEMENT UNDER THE NEW LABEL that is a claim about the agent rather than the route: the PORCINE rotaviruses are the registered agent, and no illness has been shown to be caused by them in a person. Human rotavirus disease is caused by human rotaviruses. C1 carries the species-specificity question separately, at level 2, on the porcine-like RVC detected in Brazilian children.
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.1: "Rotaviruses (RVs) are A MAJOR CAUSE OF DIARRHEA IN HUMANS AND ANIMALS, INCLUDING PIGS." The chapter gives no clinical description, severity, outcome or case count for any human infection acquired from a pig -- the Brazilian RVC detections in children (38.2.3) are reported as detections, with no illness described.
How this level was decided
RE-SCORED 2026-09-04. C2 now grades the severity of the illness the agent causes in a person, independent of how the person was exposed -- the 2026-09-01 pig-attribution reading is reversed, and C1 alone carries the source question. The pass had already written the level 2 reasoning before the cell was pulled to 1: "mild and self-limiting -- scored on what rotavirus gastroenteritis is in a country with routine medical care".
PREVIOUS ANSWER, written under the pig-attribution reading: INFERRED, AND IT MOVES WITH C1. Level 2 -- mild and self-limiting -- scored on what rotavirus gastroenteritis is in a country with routine medical care: an acute diarrhoeal illness treated with rehydration. THE FOLDER DOES NOT SUPPORT MORE THAN THAT and does not support less: it never describes the outcome of a single pig-attributed human case. THE ARGUMENT FOR LEVEL 3 is that rotavirus is a leading cause of childhood gastroenteritis worldwide and routinely hospitalises infants for dehydration, which is the level 3 label. IF YOU RULE C1 DOWN TO LEVEL 1, THIS CELL MUST GO TO LEVEL 1 WITH IT -- C1 level 1 implies C2 level 1 and validate_criteria.py checks it per entry.
C3 Herd introduction risk
Effort required to keep the agent out of the herd
Already in the herd: Present in most herds, or carried by pigs themselves, so there is no introduction event to prevent
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.4: "ROTAVIRUSES ARE UBIQUITOUS AND EVERY PIG WILL LIKELY EXPERIENCE RV INFECTION WITHIN ITS LIFETIME AT LEAST ONCE... Neonatal susceptibility combined with RV SHEDDING BY SOWS DURING FARROWING increases the chance of infection in young piglets. Rotavirus particles are shed in the feces of infected pigs. THEY ARE HIGHLY INFECTIOUS AND AS FEW AS 90 PARTICLES ARE SUFFICIENT to induce viral shedding and diarrhea in colostrum-deprived piglets. It is estimated that EACH GRAM OF FECAL MATERIAL CONTAINS 1 x 10(10) INFECTIOUS RV PARTICLES... Rotavirus is HIGHLY STABLE IN THE ENVIRONMENT AND EVEN COMPLETE DRYING WILL NOT INACTIVATE ALL VIRIONS." 38.2.10 states the conclusion: "ROTAVIRUS INFECTIONS ARE ENDEMIC IN SWINE POPULATIONS AND ELIMINATION FROM SWINE HERDS IS NOT PRACTICAL." The second document in the folder confirms it in healthy animals: degroof_2025 found rotavirus A at two weeks of age and rotaviruses B, C and H around weaning on seven Dutch farms selected for having LESS THAN 5% of pens showing post-weaning diarrhoea.
How this level was decided
Level 1, and the chapter states it twice over: every pig meets it, and elimination from herds is not practical. There is no introduction event to prevent. NOTE THE de Groof CORROBORATION, because it is the strongest kind available for this level: the farms in that study were chosen for being HEALTHY -- under 5% of pens with diarrhoea, 25 kg by ten weeks, no batch antimicrobial use for six months -- and all four rotavirus species turned up in them anyway, on schedule, on every farm.
C4 Detection difficulty
Difficulty of recognizing and confirming infection
Laboratory-dependent: The presentation does not point to this disease specifically, but local or regional laboratories can confirm it with a validated assay once it is suspected
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.8: "Clinical signs of RV infection are SIMILAR TO OTHER ENTERIC PATHOGENS AND, THEREFORE, A DIAGNOSIS CANNOT BE MADE WITHOUT LABORATORY TESTING. However, the fact that RV CAN ALSO PRODUCE SUBCLINICAL INFECTIONS should be a consideration when establishing a diagnosis... RT-PCR IS THE MOST COMMON DIAGNOSTIC METHOD used to detect RV and, if quantitative, can determine viral concentrations within a sample. The development of MULTIPLEX RT-PCR TESTS containing primers for several enteric viruses allows for the simultaneous detection of multiple diarrhea-causing pathogens in a clinical sample. MULTIPLEX REAL-TIME RT-PCR (RT-qPCR) METHODS CAN DISTINGUISH BETWEEN RVA, RVB, AND RVC." Also available: "immunochromatography strip tests, COMMERCIAL ELISA KITS, cell culture immunofluorescence, immune electron microscopy."
How this level was decided
Level 2. The chapter says in terms that the clinical picture cannot make the diagnosis, so it is not level 1; and confirmation is a routine multiplex enteric RT-PCR panel run by every regional diagnostic laboratory, which additionally speciates RVA, RVB and RVC in one test. That is the level 2 label. NOTE THE INTERPRETIVE PROBLEM THAT DOES NOT CHANGE THE LEVEL BUT SHOULD REACH A BRIEF: a positive result does not establish causation, because subclinical infection is common and the de Groof study found all four species in clinically healthy pigs. Finding rotavirus in a scouring litter is not the same as finding the cause of the scour.
C5 Production cost
Financial impact on the infected farm's cost of production
Minor: Small and generally short-lived losses with little effect on overall cost of production
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c5l2, minor disease on most farms though start up herds can have more problems before herd immunity is established."
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.6: "Studies in conventionally reared piglets have reported MORTALITY RATES BELOW 20%, but higher mortality rates have been reported in diagnostic cases... Mortality rates can be extremely high (86-100%) IN GNOTOBIOTIC PIGLETS." On recovery: "Diarrhea in pigs infected at <7 days of age lasts for 1-10 days and PIGS THAT RECOVER USUALLY RAPIDLY RETURN TO NORMAL BODY WEIGHT. In piglets >7 days of age, LESS SEVERE CLINICAL SIGNS, SHORTER DISEASE DURATION, AND FEWER DEATHS are generally observed." 38.2.1 on what makes it worse: "RV infections can occur IN COMBINATION WITH ENTERIC PATHOGENIC BACTERIA, LEADING TO INCREASED DISEASE SEVERITY, including dehydration, diarrhea, and death", and 38.2.6 names enterotoxigenic E. coli and Clostridium perfringens type A specifically.
How this level was decided
INFERRED. Level 2 -- small and generally short-lived losses. THE DECIDING FACT IS THE RECOVERY CLAUSE: pigs that recover rapidly return to normal body weight, and the disease is a one-to-ten-day scour in a population that meets the virus once and then carries immunity, which is the shape you used to move porcine parvovirus 1 down to level 2 today ("losses due to clinical disease when they occur are SHORT LIVED and one-off"). It scores level with neonatal and post-weaning colibacillosis, which is the right company -- the same age group, the same syndrome, often the same litter. THE ARGUMENT FOR LEVEL 3 is that this is not one disease event per herd but a continuous drip through every farrowing group, and that the sub-20% mortality figure is the conventional-piglet number rather than the diagnostic-case number, which the chapter says is higher. THE 86-100% FIGURE IS GNOTOBIOTIC AND MUST NOT BE CARRIED into a brief as a field mortality rate.
C6 Market impact
Duration of material disruption to pork and pig markets
Negligible: Little or no material disruption to supply or demand when disease occurs on one or more farms
CONFIRMED by Eric. The assignment reached this level from the evidence, and he has reviewed and ratified it.
Confirmed by Eric. CONFIRMED. "c6l1, common agent, no market impact"
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. Rotaviruses are ubiquitous in US swine -- "every pig will likely experience RV infection within its lifetime at least once" (ch38 38.2.4) -- and no trade measure, movement restriction or consumer response to a porcine rotavirus diagnosis is recorded anywhere in the folder.
How this level was decided
INFERRED. Level 1 under the standing note SCORING/market_impact: an agent universally present and routinely diagnosed in US pigs, with no market move ever observed.
C7 Treatment potential
Potential for treatment to improve outcomes
Little: Effective pathogen-directed treatment is available and works, or animals recover acceptably without it
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.10: "SUPPORTIVE TREATMENT FOR RV-AFFECTED ANIMALS INCLUDES MAINTAINING ADEQUATE AMBIENT TEMPERATURE (35 degrees C) AND FEEDING A HIGH-ENERGY DIET to weaned pigs. FLUID ADMINISTRATION WITH ELECTROLYTES OR L-GLUTAMINE TO PREVENT DEHYDRATION from diarrhea and vomiting, as well as ANTIBIOTIC THERAPY FOR CASES WITH BACTERIAL COINFECTIONS, CAN BE HELPFUL." 38.2.6 on outcome without pathogen-directed treatment: "pigs that recover usually rapidly return to normal body weight."
How this level was decided
Level 1, and it is the worked example at this level. Both clauses of the label are satisfied at once, which is unusual: supportive treatment exists, is standard, and works -- warmth, fluids, electrolytes, and antibiotics for the bacterial coinfection that does most of the killing -- and animals also recover acceptably, returning rapidly to normal body weight. There is no antiviral and none is needed, which is a different statement from the one your 2026-09-02 rule forbids: this is not "nobody treats viral disease", it is that the treatable part of the disease is dehydration and the coinfection, and both are treated.
C8 Vaccine availability
Availability of effective vaccines or bacterins
Available but inconsistent: Commercial or autogenous vaccines exist in the US but protection may be inconsistent
Basis. THE ENTRY IS A GROUP. ch38 38.2.1: nine rotavirus species are recognised, and "AMONG THEM, RVA, RVB, RVC, AND RVH ARE COMMONLY REPORTED IN PIGS." Historically RVA was thought the most prevalent and pathogenic, "BUT RVC HAS BEEN IDENTIFIED AS A SIGNIFICANT CAUSE OF ENTERITIS IN NEONATAL PIGS", while RVB and RVH affect younger and older pigs respectively. ch38 38.2.10: "COMMERCIAL VACCINES ARE AVAILABLE FOR RVA, BUT NOT FOR RVB OR RVC. In general, KILLED VACCINES ARE NOT AS EFFECTIVE as modified live or attenuated viral strains. Also, MATERNALLY-ACQUIRED ANTIBODIES IN PIGLETS MAY INTERFERE WITH LIVE RV VACCINES." 38.2.9 on why coverage is hard: "THERE IS NO CROSS-PROTECTION BETWEEN VIRUSES IN DIFFERENT RV SPECIES", within-species cross-protection is "scarce in pigs", "RV strains belonging to different lineages within a genotype DO NOT CROSS-NEUTRALIZE EFFECTIVELY", and "vaccines should include the most prevalent RV genotypes in a geographic region to provide the best range of protection". 38.2.10 also records what producers do instead: "EXPOSURE OF PREGNANT SOWS/GILTS TO INFECTIOUS RV (FEEDBACK) IS COMMONLY USED to stimulate maternal immunity."
How this level was decided
Level 2, and the group structure is what makes it clean rather than complicated. A commercial vaccine is available in the US, so this is not level 3; the disease plainly warrants vaccinating, so it is not the "not needed" half of level 1. What holds it at level 2 is that the product covers ONE of the four member species -- and the chapter says there is NO cross-protection between rotavirus species, so the RVA vaccine does nothing against RVC, which it also calls a significant cause of neonatal enteritis. Add maternal antibody interference, poor cross-neutralisation between lineages within a genotype, and the fact that herds fall back on feedback, and "available but protection may be inconsistent" is an understatement rather than a stretch.
Levels and evidence are generated from data/assignments/porcine_rotaviruses.yml; the overview is authored in data/overviews/porcine_rotaviruses.md. Do not hand-edit this page — corrections go in data/assignments/CORRECTIONS.yml.
Quoted material marked Basis is from Zimmerman JJ, Karriker LA, Ramirez A, Schwartz KJ, Stevenson GW, Zhang J, eds. Diseases of Swine, 12th edition. Hoboken: Wiley Blackwell, 2025 — except where another source is named in the quotation itself.